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Naturally processed HLA class I bound peptides from c-myc-transfected cells reveal allele-specific motifs
1Division of Immunogenetics, College of Physicians and Surgeons of Columbia University, New York, NY 10032.
Insights
Researchers analyzed peptides bound to HLA molecules from c-myc transfected cells, identifying three distinct structural motifs. One peptide, HEETPPTTS, matched a region of the c-myc protein, suggesting potential immune targets.
Area of Science:
- Immunology
- Molecular Biology
- Oncology
Background:
- Peptides naturally processed and presented by Major Histocompatibility Complex (MHC) class I molecules are crucial for T-cell recognition.
- The c-myc oncogene is frequently dysregulated in various cancers, making its protein products potential targets for immunotherapy.
Purpose of the Study:
- To characterize naturally processed peptides bound to human leukocyte antigen (HLA)-A2, HLA-A68, and HLA-B40 molecules.
- To identify potential tumor-associated antigens derived from the c-myc protein.
Main Methods:
- Isolation and sequence analysis of peptides naturally bound to HLA-A2, HLA-A68, and HLA-B40 molecules from c-myc transfected lymphoblastoid B cell lines.
- Grouping of peptide sequences based on structural motifs and comparison with known peptide-binding specificities.
Main Results:
- Forty-three peptide sequences were identified and categorized into three distinct structural motifs.
- One motif corresponded to previously reported HLA-A2 and HLA-A68 binding patterns.
- A novel motif associated with HLA-B40 was identified, characterized by specific amino acid residues in the peptide's binding groove.
- A peptide, HEETPPTTS, within the HLA-B40 motif was found to be 100% homologous to residues 243-251 of the c-myc protein.
Conclusions:
- Naturally processed peptides bound to HLA-A2, HLA-A68, and HLA-B40 molecules exhibit distinct structural motifs.
- The identification of a c-myc-derived peptide bound to HLA-B40 suggests its potential as a target for cancer immunotherapy.
Abstract:
Naturally processed peptides, bound to HLA-A2, A68, B40 molecules, were isolated from a c-myc transfected lymphoblastoid B cell lines for sequence analysis. Forty-three sequences of bound peptides could be grouped into three structural motifs. One of the peptide sequences obtained, SLLPAIVEL, was identical to a previously reported peptide bound to HLA-A2.1 and was used for grouping HLA-A2-bound peptides. A second motif, identical to that previously reported for HLA-A68-bound peptides, was also observed. A distinct third motif, consistent with the structure of the HLA-B40 "45 pocket," was observed. The peptides within this group contained glutamate in position 2, usually followed by a hydrophobic residue in positions 3 and 9. Within this motif group of peptides bound to MHC class I molecules, one peptide, HEETPPTTS, was 100% homologous to residues 243-251 of the c-myc protein.